Allowance for Credit Losses (Detail) (USD $)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of the year	$ 44,661,000	$ 40,199,000
Recoveries	(31,531,000)	(25,171,000)
Provisions	11,117,000	29,633,000
Balance, end of the year	$ 24,247,000	$ 44,661,000

A valuation allowance for financing receivables that are expected to be uncollectible.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-URI http://asc.fasb.org/extlink&oid=6965416&loc=SL6953423-111524

-Subparagraph (c)(1)

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Charge to expense for financing receivables that are expected to be uncollectible.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesProvisions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reduction to the allowance for credit losses related to collections on financing receivables which have been partially or fully charged off as bad debts.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRecoveries
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration